Packing cone with doubly curved surfaces



July 11, 1967 E. T. SKINNER PACKING CONE WITH DOUBLY CURVED SURFACES 8 w, 2 w v V O 5 l1 2 2 L 2 6 X 4 l4 2 E12! 1 1 I v 1 O 3 2 I 2 2 2 2 EDWARD T SKINNER INVENTOR.

BY A9. M

United States Patent M 3,330,569 PACKING CONE WITH DOUBLY CURVED SURFACES Edward T. Skinner, 4320 Valley Ridge Road,

Dallas, Tex. 75220 I Filed Mar. 19, 1964, Ser. No. 353,214 2 Claims. (Cl. 277-212) This invention relates to packing glands, and more particularly to a packing gland cone of configuration for assuring a seal around a polish rod in a pump stuffing box.

In prior art patents such as illustrated by Patents 3,050,312, 3,002,776 3,013,831 and 2,994,549, various types of rubber cones for stuffing boxes are illustrated. The present invention is directed to a new and improved rubber cone for use in stuffing boxes of the type illustrated in the above patents but which is self-aligning, provides a positive pressure-dependent seal around the polish rod, provides for lubrication, and maintains the polish rod wiped clean.

In accordance with the invention, there is provided a hollow resilient cone having an axial cylindrical aperture. The outer surface is outwardly and downwardly curved to the cone base. The inner surface has a compound curve with a lip extending in the direction of said aperture. The inner curvature of one cone serves to bear against the outer surface of the other cone with the contact zone being characterized by curvatures of opposite senses.

For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawing in which:

The drawing is a view partially in section illustrating rubber cones and installation thereof.

The drawing illustrates a packing for a polish rod 10. Rod may extend into an oil well. It is to be reciprocated up and down to raise oil from the well. At the same time, it is necessary to maintain a seal around the rod 10. Rod 10 will pass through a stufiing box such as illustrated in FIGURE 1 of Patent 3,050,312.

The present invention is directed particularly to the installation which is self-aligning, self-lubricating and which provides a positive seal. This is accomplished in accordance with the present invention through the use of a new cone of the type shown in the drawing.

Such new cones are employed as shown in the drawing when two cones 12 and 13 are provided with central openings 14 and 15, respectively, through which the polish rod 10 passes. The stufling box is indicated generally by the section 20.

Cones 12 and 13 are identical. Cone 13 has a flat bottomed cylindrical base 21, a vertical or cylindrical wall portion 22, a curved portion 23, a straight portion 24 and an upper curved lip 25. The zones 22-25 form the outer surface of the cone. The inner surface of the cone is formed by a straight portion 26, a curved portion 27 and a downwardly-directed sealing lip 28. The lips 25 and 28 serve to prevent dirt from entering between the packing and the rod 10.

The outer cylindrically convex portion 24, 25 and inner cylindrically convex portion 27 of cone 12 permit rocking motion of one cone onto the other cone for accurate positioning of the cones with respect to the rod 10. The cylindrically convex portions also facilitate working of the packing assembly as the polish rod 10 deflects due to load variations or from mis-ali-gnment of the smiling box and the rod. Although the cones have been illustrated as having a cylindrically convex portion 23 and 3,330,569 Patented July 11, 1967 25 with a straight portion 24 therebetween, they can be curved through the entire zone if desired. Similarly, the portions 26 and 27 can be curved continuously rather than having a limited curve portion and a straight section. However, in the contact zone between the inner surface of unit 13 and the outer surface of unit 12 the surfaces are both cylindrically convex. This is in the region of a line or cylindrical section parallel to the axis of the polish rod 10 at a radius midway between the radius of the aperture 15 and the cylindrical portion 22.

In practice, two of the cones illustrated in the drawing are ordinarily installed in a stufling box in place of the four cones identified with the reference character 46 in Patent 3,050,312. The wiping action and sealing action are positive when cones of the present invention are employed. The downwardly-extending lip 28 provides a sealing action which is pressure dependent. That is, as the pressure underneath the cones increases, the downwardlyextending lip 28 is forced more firmly into contact with the walls of the polish rod.

The cones are made from rubber or a rubber-like material, the character, quality and physical properties of which are selected in dependence upon the application to which the cones are employed. In an oil well installation where oil and salt water are the principal factors controlling the environment of the packing gland, the material is generally rubber, the specific composition of which depends on the pressures to be expected and the size of the stuffing box and the size of the polish rod. For pumps handling corrosive materials, a base material other than rubber may be found more preferable. In any case, the cone is formed of a resilient material which can be compressed and which will be responsive to pressure for sealing purposes.

An upper cone, a wiper cone 30 is also generally employed in a given stuifing box application, indicated in Patent 3,050,312. In accordance with this invention, the wiping cone 30 is located above cones 12 and 13 and in the location of the wiping cone 52 of the above-identified patent. The cone 30 is characterized by pressure-actuated sealing lips 31 with an outer surface of the same configuration as the portions 23, 24 and 25 of cone 13. The inner surface is the same shape as the zones 26, 27 and 28 of cone 13. It is to be understood that the drawing is figurative only, with the understanding that the stuffing box element will be provided as shown in FIGURE 1 of Patent 3,050,312. The present invention is directed primarily to the cones and an assembly thereof. The particular configuration of the surfaces of the cones provides for a positive seal and maximum protection to the polish rod.

Four of the wiping cones 30 can be employed in place of the two sealing cones 12 and 13. However, it has been found to be preferable to employ the two units 12 and 13 rather than four of the units 30 in the lower stuflfing box. Two cones 12 and 13 provide a positive seal and will withstand working of the polish rod.

Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest them selves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims.

What is claimed is:

1. In a stufling box system for maintaining a seal around a polish rod the combination which comprises a pair of resilient hollow cones each having an axially directed cylindrical aperture at the top thereof to receive and engage said polish rod at two spaced points, said cones each having outer cylindrically convex surfaces which simply curve outward and downward to a cylindrical cone base, and inner cylindrically convex surfaces which curve inward and upward from said base with a first of said cones nested Within the second cone and engaging the inner cylindrically convex surface of said second cone with its outer cylindrically convex surface in an annular zone substantially confined to a zone midway between the surface of said rod and the outer surface of said cylindrical cone base which contact zone may vary as the inner surface of said second cone moves along the outer surface of said first cone in response to lateral deflections or misalignment of said polish rod.

2. The combinatio t forth in claim 1 in which the said curvatures of the inner surface of said second cone and outer surface of said first cone differ in degree.

References Cited Hanner 277 212 X LAVERNE D. GEIGER, Primary Examiner.

JEFFREY MEDNICK, Assistant Examiner. 

1. IN A STUFFING BOX SYSTEM FOR MAINTAINING A SEAL AROUND A POLISH ROD THE COMBINATION WHICH COMPRISES A PAIR OF RESILIENT HOLLOW CONES EACH HAVING AN AXIALLY DIRECTED CYLINDRICAL APERTURE AT THE TOP THEREOF TO RECEIVE AND ENGAGE SAID POLISH ROD AT TWO SPACED POINTS, SAID CONES EACH HAVING OUTER CYLINDRICALLY CONVEX SURFACES WHICH SIMPLY CURVE OUTWARD AND DOWNWARD TO A CYLINDRICAL CONE BASE, AND INNER CYLINDRICALLY CONVEX SURFACES WHICH CURVE INWARD AND UPWARD FROM SAID BASE WITH A FIRST SAID CONES NESTED WITHIN THE SECOND CONE AND ENGAGING THE INNER CYLINDRICALLY CONVEX SURFACE OF SAID SECOND CONE WITH ITS OUTER CYLINDRICALLY CONVEX SURFACE IN AN ANNULAR ZONE SUBSTANTIALLY CONFINED TO A ZONE MIDWAY BETWEEN THE SURFACE OF SAID ROD AND THE OUTER SURFACE OF SAID CYLINDRICAL CONE BASE WHICH CONTACT ZONE MAY VARY AS THE INNER 